US5629472A - Method of minimizing bias and achieving mode alignment by trimming a vibrating rate sensor - Google Patents
Method of minimizing bias and achieving mode alignment by trimming a vibrating rate sensor Download PDFInfo
- Publication number
- US5629472A US5629472A US08/458,186 US45818695A US5629472A US 5629472 A US5629472 A US 5629472A US 45818695 A US45818695 A US 45818695A US 5629472 A US5629472 A US 5629472A
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- Prior art keywords
- transducer
- primary
- pick
- signal
- vibrating
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
- G01C19/567—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using the phase shift of a vibration node or antinode
- G01C19/5691—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using the phase shift of a vibration node or antinode of essentially three-dimensional vibrators, e.g. wine glass-type vibrators
Definitions
- the present invention relates to a method of tuning a vibrating rate sensor and relates particularly, but not exclusively, to a method of balancing and mode alignment of the vibrating portion of a vibrating rate sensor.
- FIG. 1 illustrates diagrammatically a single axis rate sensor of the type described in GB 2061502 and GB 2154739.
- the cylinder of the vibrating rate sensor is driven into resonance by applying an oscillating electronic signal to the drive transducers.
- the vibration pattern, viewed from the top, of the resonance mode is shown in FIG. 2. It will be seen that there are anti-nodes of maximum radial vibration and nodes of minimal radial vibration present.
- the primary loop maintains this resonance by ensuring a 90 degree phase shift between the primary drive transducer and primary pick-off transducer.
- the resonance mode rotates with respect to the cylinder, and a signal can be detected on the secondary pick-off transducer.
- This signal is amplified and fed back to the secondary drive transducer in order to null it to zero.
- the strength of this nulling signal is proportional to rotating rate.
- the signal is demodulated and output as a DC rate signal.
- the vibration pattern can have a different shape than that shown in FIG. 2. However, the vibration pattern must have nodes and anti-nodes occurring cylindrically around the perimeter of the cylinder.
- the cylinder does not have to be driven exactly at 50 resonance--but in practice it is desirable so to do.
- the resonant body neither has to be circular, nor cylindrical. Hemispheres and rings can be used. However, it is desirable that the oscillating modes seen by primary and secondary electronic circuits (referred to as the primary and secondary resonance) have the same, or nearly the same resonant frequency.
- GB 2061502 describes a metal cylinder, closed at one end and supporting by a stem, which is driven into resonance using piezo-electric elements stuck onto the metal cylinder as shown in FIG. 3. Piezo-electric elements are also used to pick-off the movement.
- GB 2154739 describes a similar device of unitary construction made from piezo-electric material where the drive and pick-off pieces are formed by polarizing the material between electrode regions as shown in FIG. 4.
- GB 2061502 illustrates in FIG. 3 of that reference that, because of the difficulty of mounting a secondary pick-off transducer exactly at a nodal position, it is more convenient to provide a pair of secondary pick-off transducers with their two outputs combined together in such a manner as to provide a zero output in the absence of the rotation. Two secondary drive transducers are then required opposite the pair of secondary pick-off transducers. The outputs of the secondary pick-off transducers are adjusted to give maximum rejection of the applied radial vibration. Then the signals applied to the secondary drive transducers are adjusted.
- GB 2154739 illustrates that the device described in GB 2061502 can be made entirely from a unitary piece of piezo-electric material, and that the transducing action of electrical input to the mechanical output can be made to take place within the resonator itself.
- Another drawback of the arrangement given in GB 2061502 is that it is not efficient in the number of bond wires and/or transducing elements. Thus one more bond wire is required in the secondary pick-off transducer and one more in the secondary drive transducer.
- the present invention overcomes the problems associated with the above mentioned prior rate sensors by providing a method of mechanically balancing the cylinder by the removal of material, and then trimming the effective electrode positions to minimize bias.
- the present invention is applicable to both the devices described in the above mentioned patents, together with other similar rotation rate sensors based on resonating hemispheres, cylinders, and rings.
- the present invention provides a method of mechanically balancing the vibration portion of a vibrating rate sensor of the type having primary and secondary drive transducers, and primary and secondary pick-off transducers, the method including the following steps;
- the phase of the primary pick-off is at 90 degrees with respect to the primary drive
- the method includes the step of repeating steps (a) to (f) iteratively until the frequency difference is within a desired amount.
- a second embodiment of the present invention discloses a method of minimizing bias and achieving mode alignment by trimming the effective transducer position of a vibrating rate sensor of the type having primary and second drive transducers and primary and secondary pick-off transducers the method including the following steps;
- Advantageously material is removed from a position clockwise with respect to the primary drive electrode if the in-phase component of the secondary pick-off is in anti-phase with respect to the in-phase signal of the primary pick off, and from a position anti-clockwise with respect to the primary drive electrode if the in phase component of the secondary pick-off signal and the signal of the primary pick-off are in positive phase.
- the above described method is repeated until the in-phase component of the secondary pick-off signal with respect to the in-phase component of the primary pick-off signal is less than a given amount ideally zero ration.
- a vibrating rate sensor when tuned in accordance with one or the other of the above described methods is also considered to be novel.
- a vibrating rate sensor suitable for being tuned in accordance with one or both of the above mentioned methods may comprise primary drive transducers split asymmetrically on one side of a vibrating portion thereof and complete on another side thereof.
- the primary drive transducers may be split symmetrically on one side of the vibrating portion thereof and complete on another side thereof.
- the primary drive electrodes may be complete on both sides of a vibrating portion thereof but angularly displaced so as to facilitate swinging of the effective electrode position on either side of a mean position.
- FIG. 1 is a schematic diagram of a single axis rate sensor of the type described in GB 2061502 and GB 2154739,
- FIG. 2 is a diagrammatic representation of the vibration pattern produced in the vibrating cylinder of a single axis rate sensor
- FIG. 3 is a perspective view of a vibrating cylinder structure for inclusion in a typical vibrating rate sensor
- FIG. 4 illustrates a device similar to that shown in FIG. 1 but of unitary construction made from piezo-electric material where the drive and pick-off transducers are formed by polarizing the material between electrode regions,
- FIG. 5 is a schematic representation of a vibratory rate sensor capable of being tuned in accordance with the present invention.
- FIGS. 6 to 8 illustrate in more detail alternate electrode positions on the cylinder shown in FIG. 5, and
- FIGS. 9A to 9C illustrate the removal of a small amount of material from a portion of the vibrating cylinder.
- FIG. 5 illustrates a vibrating rate sensor of the type shown in FIG. 1 and described above, but having the additional features of the primary and secondary pick-off transducers 18, 20 being connected to charge amplifiers 22, 24 and the inner electrode 26 and the secondary drive electrodes 28, are connected to earth.
- the primary pick-off electrodes 18 are connected together, as are the secondary pick-off electrodes 20.
- the primary drive electrodes 30, 32 are split on one side of the vibrating cylinder 34 only, and connected together via a resistor network 36, 38.
- FIGS. 6 to 8 illustrate a number of alternative split drive electrode positions.
- Step A A sinusoidal signal is applied to the primary drive transducers 30, 32 through resistors 36, 38, respectfully;
- Step B The frequency of the sinusoidal signal is adjusted until a desired vibration mode is excited and the phase detected by of the primary pick-off transducers 18 is at 90 degrees with respect to the sinusoidal applied to the transducers 30,; 32 primary drive;
- Step C The frequency (f np ) of the primary vibratory mode is measured
- Step D Steps A and B are repeated for the secondary drive electrodes 28;
- Step E The frequency of the secondary vibratory mode (f ns ) is measured
- Step F A small amount of material is removed from a portion of the vibrating cylinder 34 adjacent either the drive or the pick-off tranducers of whichever mode corresponds to the mode having the lowest resonant frequency so as to reduce the frequency difference to within a desired amount.
- Steps A to F may be repeated iteratively until the frequency difference is within a particularly desired amount ideally zero.
- the frequency of a mode is altered by filing material above an electrode relating to that mode. This has the effect of reducing mass in motion in the vibration (modal mass) and since the resonant frequency f is related to the mass by: f ⁇ 1/ ⁇ M, the resonant frequency is increased.
- a second embodiment of the present invention discloses a method of minimizing bias and achieving mode alignment by trimming the effective electrode position, the method including exciting the primary mode as outlined in steps A to E above and monitoring the output of the secondary pick-off transducer on, for example, an oscilloscope (not shown). Material is then removed from the top rim between the electrodes until the secondary signal component in phase with respect to the primary pick-off is zero. In other words, until the secondary pick-off signal is 90 degrees out of the phase with respect to the primary pick-off signal.
- Material is removed clockwise with respect to the primary drive electrode if the out from the secondary pick-off transducers 20 are less than 90 degrees out of phase with respect to the output from the primary pick-off tranducers 18, and at a position anti-clockwise with respect to the primary drive electrode if the signals are greater than 90 degrees out of phase.
- the detail of which direction with respect to the primary drive electrode material should be removed depends upon the relative dispositions of the primary pick-off and secondary pick-off electrodes. The process is iterated until the in-phase component of the output signal of the secondary pick-off transducer 20 with respect to the output signal of the primary pick-off transducer 18 is less than a given amount (typically 0.01).
- the above mentioned steps may be repeated to improve the accuracy of the tuning process. It should be noted that in practice it is difficult (or time consuming) to reduce the component of the output signal of the secondary pick-off transducers 20 which is in quadrature with respect to the output signal of the primary pick-off transducers 18, to zero by material removal.
- FIGS. 6 to 8 illustrate different arrangements for the vibrating electrode configuration on the cylinder 34.
- FIG. 6 illustrates the primary drive electrodes 30, 32 split asymmetrically on one side of the vibrating cylinder 34, but complete on the other as shown by 30a.
- FIG. 7 illustrates the primary drive electrodes 30, 32 split symmetrically on one side of the cylinder, but complete on the other as shown by 30a.
- FIG. 8 illustrates the primary drive electrodes 30, 32 complete on both sides of the vibrating cylinder 34. However these electrodes 30, 32 are angularly displaced such that by varying the electrical drive to the electrodes 30, 32, it is possible to swing the effective electrode position either side of a mean position.
- the quadrature component of the output signal of the secondary pick-off electrodes 20 with respect to the output signal of the primary pick-off electrode 18 can be reduced to zero.
- the split and asymmetrical electrode patterns shown in FIG. 6 to 8 are more efficient in terms of bond wires and electrodes than the equivalent scheme given in GB 2154739.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Gyroscopes (AREA)
Abstract
Description
Claims (4)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/458,186 US5629472A (en) | 1992-04-24 | 1995-06-02 | Method of minimizing bias and achieving mode alignment by trimming a vibrating rate sensor |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9208953 | 1992-04-24 | ||
GB9208953A GB2266588B (en) | 1992-04-24 | 1992-04-24 | Vibrating rate sensor tuning |
US08/051,388 US5445007A (en) | 1992-04-24 | 1993-04-23 | Method of balancing a vibrating rate sensor by removing a portion of the vibrating cylinder |
US08/458,186 US5629472A (en) | 1992-04-24 | 1995-06-02 | Method of minimizing bias and achieving mode alignment by trimming a vibrating rate sensor |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/051,388 Division US5445007A (en) | 1992-04-24 | 1993-04-23 | Method of balancing a vibrating rate sensor by removing a portion of the vibrating cylinder |
Publications (1)
Publication Number | Publication Date |
---|---|
US5629472A true US5629472A (en) | 1997-05-13 |
Family
ID=10714531
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/051,388 Expired - Lifetime US5445007A (en) | 1992-04-24 | 1993-04-23 | Method of balancing a vibrating rate sensor by removing a portion of the vibrating cylinder |
US08/458,186 Expired - Lifetime US5629472A (en) | 1992-04-24 | 1995-06-02 | Method of minimizing bias and achieving mode alignment by trimming a vibrating rate sensor |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/051,388 Expired - Lifetime US5445007A (en) | 1992-04-24 | 1993-04-23 | Method of balancing a vibrating rate sensor by removing a portion of the vibrating cylinder |
Country Status (5)
Country | Link |
---|---|
US (2) | US5445007A (en) |
EP (1) | EP0567340B1 (en) |
JP (1) | JP3269699B2 (en) |
DE (1) | DE69310805T2 (en) |
GB (1) | GB2266588B (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6089090A (en) * | 1996-10-15 | 2000-07-18 | Ngk Insulators, Ltd. | Vibration gyro sensor |
US6698271B1 (en) * | 1998-07-13 | 2004-03-02 | Bae Systems, Plc. | Process for reducing bias error in a vibrating structure sensor |
US20070039386A1 (en) * | 2005-08-08 | 2007-02-22 | Stewart Robert E | Bias and quadrature reduction in class II coriolis vibratory gyros |
US20090064782A1 (en) * | 2007-09-11 | 2009-03-12 | Evigia Systems, Inc. | Sensor and sensing method utilizing symmetrical differential readout |
US20100089158A1 (en) * | 2008-10-14 | 2010-04-15 | Watson William S | Vibrating structural gyroscope with quadrature control |
US10466268B2 (en) * | 2015-05-15 | 2019-11-05 | Invensense, Inc. | Offset rejection electrodes |
US11231441B2 (en) * | 2015-05-15 | 2022-01-25 | Invensense, Inc. | MEMS structure for offset minimization of out-of-plane sensing accelerometers |
US11346668B2 (en) * | 2019-12-12 | 2022-05-31 | Enertia Microsystems Inc. | System and method for micro-scale machining |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3175489B2 (en) * | 1994-08-24 | 2001-06-11 | 三菱電機株式会社 | Vibrating gyroscope and vibrating gyroscope inspection device |
GB2292609B (en) * | 1994-08-24 | 1998-04-15 | British Aerospace | Method for matching vibration mode frequencies on a vibrating structure |
GB2299669B (en) * | 1995-04-07 | 1998-12-16 | British Aerospace | Method for actively balancing a vibrating structure gyroscope sensing element structure |
GB2335273B (en) * | 1998-03-14 | 2002-02-27 | British Aerospace | A two axis gyroscope |
JP2000346865A (en) * | 1999-03-26 | 2000-12-15 | Ngk Insulators Ltd | Sensitivity adjusting method for acceleration sensor element |
JP4331211B2 (en) * | 2004-02-04 | 2009-09-16 | アトランティック・イナーシャル・システムズ・リミテッド | Method to reduce bias error in vibrating structure gyroscope |
US7617727B2 (en) * | 2006-04-18 | 2009-11-17 | Watson Industries, Inc. | Vibrating inertial rate sensor utilizing split or skewed operational elements |
WO2007120158A1 (en) * | 2006-04-18 | 2007-10-25 | Watson Industries, Inc. | Solid state gyroscope electrodes for adjustability |
US7526957B2 (en) * | 2006-04-18 | 2009-05-05 | Watson Industries, Inc. | Vibrating inertial rate sensor utilizing skewed drive or sense elements |
GB201008526D0 (en) | 2010-05-21 | 2010-07-07 | Silicon Sensing Systems Ltd | Sensor |
US20160245653A1 (en) * | 2013-04-30 | 2016-08-25 | Sangtae Park | Cylindrical resonator gyroscope |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2061502A (en) * | 1979-10-19 | 1981-05-13 | Marconi Co Ltd | A Sensor for Detecting Rotational Movement |
EP0153189A2 (en) * | 1984-02-22 | 1985-08-28 | National Research Development Corporation | Gyroscopic devices |
EP0171378A1 (en) * | 1984-07-27 | 1986-02-12 | Watson Industries, Inc. | Angular rate sensor |
EP0405152A2 (en) * | 1989-05-29 | 1991-01-02 | Japan Aviation Electronics Industry, Limited | Method for adjusting a spinning piezoelectric beam of a dual-axis angular rate sensor |
US5018858A (en) * | 1988-10-04 | 1991-05-28 | British Aerospace Public Limited Company | Ring resonator gyroscope control system with gain difference equalization |
US5098188A (en) * | 1989-02-15 | 1992-03-24 | British Aerospace Plc | Method and apparatus for eliminating kerr effects in a ring gyro |
US5218867A (en) * | 1989-07-29 | 1993-06-15 | British Aerospace Public Limited Company | Single axis attitude sensor |
US5349261A (en) * | 1992-03-30 | 1994-09-20 | Murata Manufacturing Co., Ltd. | Vibrator |
-
1992
- 1992-04-24 GB GB9208953A patent/GB2266588B/en not_active Revoked
-
1993
- 1993-04-20 JP JP09284193A patent/JP3269699B2/en not_active Expired - Fee Related
- 1993-04-22 DE DE69310805T patent/DE69310805T2/en not_active Expired - Fee Related
- 1993-04-22 EP EP93303166A patent/EP0567340B1/en not_active Expired - Lifetime
- 1993-04-23 US US08/051,388 patent/US5445007A/en not_active Expired - Lifetime
-
1995
- 1995-06-02 US US08/458,186 patent/US5629472A/en not_active Expired - Lifetime
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2061502A (en) * | 1979-10-19 | 1981-05-13 | Marconi Co Ltd | A Sensor for Detecting Rotational Movement |
EP0153189A2 (en) * | 1984-02-22 | 1985-08-28 | National Research Development Corporation | Gyroscopic devices |
GB2154739A (en) * | 1984-02-22 | 1985-09-11 | Nat Res Dev | Gyroscopic devices |
EP0171378A1 (en) * | 1984-07-27 | 1986-02-12 | Watson Industries, Inc. | Angular rate sensor |
US5018858A (en) * | 1988-10-04 | 1991-05-28 | British Aerospace Public Limited Company | Ring resonator gyroscope control system with gain difference equalization |
US5098188A (en) * | 1989-02-15 | 1992-03-24 | British Aerospace Plc | Method and apparatus for eliminating kerr effects in a ring gyro |
EP0405152A2 (en) * | 1989-05-29 | 1991-01-02 | Japan Aviation Electronics Industry, Limited | Method for adjusting a spinning piezoelectric beam of a dual-axis angular rate sensor |
US5218867A (en) * | 1989-07-29 | 1993-06-15 | British Aerospace Public Limited Company | Single axis attitude sensor |
US5349261A (en) * | 1992-03-30 | 1994-09-20 | Murata Manufacturing Co., Ltd. | Vibrator |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6089090A (en) * | 1996-10-15 | 2000-07-18 | Ngk Insulators, Ltd. | Vibration gyro sensor |
US6240781B1 (en) | 1996-10-15 | 2001-06-05 | Ngk Insulators, Ltd. | Vibration gyro sensor |
US6391672B2 (en) | 1996-10-15 | 2002-05-21 | Ngk Insulators, Ltd. | Vibration gyro sensor and method for producing vibration gyro sensor |
US6698271B1 (en) * | 1998-07-13 | 2004-03-02 | Bae Systems, Plc. | Process for reducing bias error in a vibrating structure sensor |
US7565839B2 (en) * | 2005-08-08 | 2009-07-28 | Northrop Grumman Guidance And Electronics Company, Inc. | Bias and quadrature reduction in class II coriolis vibratory gyros |
US20070039386A1 (en) * | 2005-08-08 | 2007-02-22 | Stewart Robert E | Bias and quadrature reduction in class II coriolis vibratory gyros |
US20090064782A1 (en) * | 2007-09-11 | 2009-03-12 | Evigia Systems, Inc. | Sensor and sensing method utilizing symmetrical differential readout |
US8056413B2 (en) * | 2007-09-11 | 2011-11-15 | Evigia Systems, Inc. | Sensor and sensing method utilizing symmetrical differential readout |
US20100089158A1 (en) * | 2008-10-14 | 2010-04-15 | Watson William S | Vibrating structural gyroscope with quadrature control |
EP2177875A2 (en) | 2008-10-14 | 2010-04-21 | Watson Industries, Inc. | A Vibrating Structural Gyroscope with Quadrature Control |
US8661898B2 (en) | 2008-10-14 | 2014-03-04 | Watson Industries, Inc. | Vibrating structural gyroscope with quadrature control |
US10466268B2 (en) * | 2015-05-15 | 2019-11-05 | Invensense, Inc. | Offset rejection electrodes |
US11231441B2 (en) * | 2015-05-15 | 2022-01-25 | Invensense, Inc. | MEMS structure for offset minimization of out-of-plane sensing accelerometers |
US11346668B2 (en) * | 2019-12-12 | 2022-05-31 | Enertia Microsystems Inc. | System and method for micro-scale machining |
Also Published As
Publication number | Publication date |
---|---|
DE69310805T2 (en) | 1997-09-04 |
JP3269699B2 (en) | 2002-03-25 |
DE69310805D1 (en) | 1997-06-26 |
GB2266588A (en) | 1993-11-03 |
EP0567340A1 (en) | 1993-10-27 |
GB2266588B (en) | 1995-11-15 |
US5445007A (en) | 1995-08-29 |
JPH0627129A (en) | 1994-02-04 |
EP0567340B1 (en) | 1997-05-21 |
GB9208953D0 (en) | 1992-06-10 |
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